3v Sweeping Siren Alarm - A while back I was challenged by a visitor to the website. He needed a very loud sweeping
siren type audio sound generator powered by 3v. He tried some of the commercial sirens but they were not very loud when
powered by 3v. He also said that those . . . [Circuit by David Johnson P.E., 06/24/08]

3V Sweeping Siren Alarm
The circuit uses a LTC1799 precision frequency generator from Linear
Technology. A 74HC14 hex Schmitt trigger from Texas Instruments is
also used to perform several other functions. One section is wired as
a simple 7Hz square wave oscillator.… [Designed by David A. Johnson]

American Police Car Siren (linscott) - Scroll down to locate this
circuit. The 555 on the right is wired as an alarm tone generator and the
second 555 timer on the left is wired as a low frequency astable timer which
generates a ramp waveform of about 6 seconds that is buffered....(electronic
design added 08/08/08)

British Police Car Siren - The first circuit simulates the siren of a
British police car. It uses two 555 timers in the circuit. The 555 on the right is
wired as an alarm tone generator and the second 555 timer on the left is a 1 Hz
astable multivibrater....(electronic design added 08/08/08)

Electronic Police Siren - The sound produced imitates the rise and fall of
an American police siren. When first switched on the 10u capacitors is discharged and
both transistors.… [Ron J.'s design]

Factory Siren - This circuit produces a sound similar to a factory siren.
It makes use of a 555 timer IC used as an astable multivibrator of a center frequency
of about 300Hz. The frequency is controlled by the pin 5 of the IC. When the supply is
switched ON, the capacitor charges slowly and this alters the voltage at pin 5 of the
IC hence....(added 05/07) [Radioland.nt.au]

Red Alert Star Trek Alarm - Scroll down to locate this circuit. The third
circuit simulates the "Red Alert" siren from the TV show Star Trek. It uses two 555
timers in the circuit. The 555 on the right is wired as an alarm tone generator and
the second 555 timer on the left is wired as a 1.5 second
non-symmetrical....(electronic design added 6/07)

Screamer Siren - This is a low-cost screamer circuit to add to our range of
alarm modules. It has been designed to protect your valuables on a 24 hour
basis…..(circuits added 06/09)

Simple Siren - This project is built on the third section of the PC board,
identified by "SIREN" and "Project 5." You will notice the similarity between this
circuit and the LED FLASHER circuit from project 2. The only differences are the LED
has been removed and the 22R resistor has been replaced by a mini speaker....(design
added 04/09)

Siren 100dB - This is a very loud siren and if two or more piezo's are
located in a room, the burglar does not know where the sound is coming from….

Siren circuit - This siren circuit simulates police, fire or other emergency
sirens that produce an up and down wail.…(added 07/07/07)

Siren circuit (page 84) - This circuit was requested by several
correspondents. Its purpose was to obtain more power than the siren circuit already
available on....(added 07/07/07)

Vehicle Car Siren - This siren circuit simulates police, fire or other
emergency sirens that produce an up and down wail.